Castellan and steward of a castle

'A seneschal was essentially the castle's steward or major-domo, in charge of domestic arrangements and the administration of servants.

A castellan was the governor or captain of the castle and would combine the responsibilites of a seneschal as well as being in charge of the military defenses and administration of the castle and its surrounding lands, particularly if the lord was absent.'

To me it sounds like castellan was a man that did it all, especially if the lord is absent, whilst the steward is more like a personal assistant of sorts to the lord himself.

Now I have been doing some research, and the information I gather gets me rather torn...some says the castles had a steward and doesn't mention castellan, and then the other way around...so did castles have both a castellan and a steward, or only one of the offices? Having both seems unnecessary...

Soo...I guess my question is how do I know which one to have for a castle? Do I have both? Do I only use one of the offices across my entire world? Is there something more concrete to tell them apart?

Using both at random for different castles is foolish to do, so either I need concrete information so I know for a fact which one to use, or I will only use one of the offices and completely neglect the other one.

Okay, so I think, after some more research, that castellans were appointed by a lord when he is expected to go absent. (Going to war for example) might be they are appointed long before, and are there in a just in case scenario. Meanwhile stewards took care of the day to day operations, as you say @A.M.P.

Then I start to wonder, what would a castellan do, if one was appointed, but the lord was still present? Perhaps they would just be a glorified adviser of sorts?

I would assume lords would have castellans on retainer or someone ready to step up whenever they would not be present suddenly. Its not like they had a luxury of time to find an choose someone new every time.

I would assume the castellan would have a high ranking primary occupation like a general or commander.

I think it's important to remember that we're not dealing with a unified command structure here. Titles would vary. Each castle would have its own individual organisation. Castles varied enormously in size, so the number of troops required to garrison them would vary, so the level of commander would vary.

A small castle would probably have a combined steward/castellan who was both day2day running and military commander.

Of course, when a lord was away at war, he would have taken most of the trained men with him, so the castle would have a small hard-core of (probably experienced but too old) trained men supplemented by young "volunteers". These would be expected to do no more than hold the castle, not go on military operations.

Castellan could easily be the first experience of command allowed to a son.